[GIS] How to convert a vector boundary to a raster map

convertgrassrastervector

I need to output a PNG file of a raster map overlayed with boundaries present in a vector map. The problem is, the r.out.png script only exports a raster map. My boundaries are in a vector format. When I tried to convert the vector boundaries into a raster, in order for me to combine them, the converted raster from vector contained the filled vector boundaries. I only need the lines to be present in the raster map. Is there a way to do it? I cannot use the d.rast and d.vect since I am calling the scripts in a shell script so there would not be any GRASS windows open.

Best Answer

See here for an answer: http://lists.osgeo.org/pipermail/grass-user/2011-July/061498.html

"If you want to convert the boundaries to rasterized lines instead of the area, you would first need to convert the boundaries to lines and then convert the vector lines to raster.

Also make sure that the computational region is correctly set (extents at least overlapping with the vector map and the desired resolution)."

Related Solutions

[GIS] How to save a raster and vector into a single PNG file in GRASS

Try this:

d.mon start=png
d.rast RASTER
d.vect VECTOR
d.mon stop=png

This will basically render VECTOR layer on top RASTER layer to a file called map.png.

Other things you could do with d.mon start=png - d.mon stop=png:

Type d.erase to wipe the slate clean before committing with d.mon stop=png

Include the legend with d.rast.leg:

d.mon start=png
d.rast.leg RASTER
d.vect VECTOR
d.mon stop=png

Put the legend to a separate image with d.legend:

d.mon start=png
d.legend RASTER
d.mon stop=png

Useful stuff..

[GIS] How to combine polygons in a vector with GRASS

The combination of the polygons is fairly easy to obtain in three steps:

add a new column (v.db.addcol), copy over the values from either the cat column or the textual column (v.db.update);
Update the new column again with a selection of either the categories of interest or string selection (where="MAIN_LITHO LIKE 'biotite%'" ; requires a real SQL backend like SQLite or PostgreSQL) in order to obtain the same value for all biotite entries;
Finally run v.dissolve on this new column.

Then you will have the task solved (there is no need to rasterize).

Best Answer

Related Solutions

[GIS] How to save a raster and vector into a single PNG file in GRASS

[GIS] How to combine polygons in a vector with GRASS

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